[PATCH RFC 03/18] x86/mm/pat: replace x86-speficic pg_level with generic pgtable_level
From: Mike Rapoport (Microsoft)
Date: Tue Jul 21 2026 - 12:36:20 EST
change_page_attr() implementation uses x86-specific enum pg_level to
track page table levels.
In preparation to moving core parts of change_page_attr() to common
code, replace usage of enum pg_level and it's values with the generic
enum pgtable_level and the values it defines.
Extend the generic enum pgtable_level with PGTABLE_LEVEL_NONE and
PGTABLE_LEVEL_NUM to match the numeric values from enum pg_level. This
is safe because nothing relies on the numeric values of PGTABLE_LEVEL_*
constants.
No functional change intended.
Assisted-by: Copilot:claude-opus-4.8
Signed-off-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
---
arch/x86/mm/pat/set_memory.c | 56 ++++++++++++++++++++++----------------------
include/linux/pgtable.h | 6 ++++-
2 files changed, 33 insertions(+), 29 deletions(-)
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index 9382f1d6194f..328805933d4d 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -80,7 +80,7 @@ static inline pgprot_t cachemode2pgprot(enum page_cache_mode pcm)
}
#ifdef CONFIG_PROC_FS
-static unsigned long direct_pages_count[PG_LEVEL_NUM];
+static unsigned long direct_pages_count[PGTABLE_LEVEL_NUM];
void update_page_count(int level, unsigned long pages)
{
@@ -97,9 +97,9 @@ static void split_page_count(int level)
direct_pages_count[level]--;
if (system_state == SYSTEM_RUNNING) {
- if (level == PG_LEVEL_2M)
+ if (level == PGTABLE_LEVEL_PMD)
count_vm_event(DIRECT_MAP_LEVEL2_SPLIT);
- else if (level == PG_LEVEL_1G)
+ else if (level == PGTABLE_LEVEL_PUD)
count_vm_event(DIRECT_MAP_LEVEL3_SPLIT);
}
direct_pages_count[level - 1] += PTRS_PER_PTE;
@@ -109,9 +109,9 @@ static void collapse_page_count(int level)
{
direct_pages_count[level]++;
if (system_state == SYSTEM_RUNNING) {
- if (level == PG_LEVEL_2M)
+ if (level == PGTABLE_LEVEL_PMD)
count_vm_event(DIRECT_MAP_LEVEL2_COLLAPSE);
- else if (level == PG_LEVEL_1G)
+ else if (level == PGTABLE_LEVEL_PUD)
count_vm_event(DIRECT_MAP_LEVEL3_COLLAPSE);
}
direct_pages_count[level - 1] -= PTRS_PER_PTE;
@@ -120,17 +120,17 @@ static void collapse_page_count(int level)
void arch_report_meminfo(struct seq_file *m)
{
seq_printf(m, "DirectMap4k: %8lu kB\n",
- direct_pages_count[PG_LEVEL_4K] << 2);
+ direct_pages_count[PGTABLE_LEVEL_PTE] << 2);
#if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)
seq_printf(m, "DirectMap2M: %8lu kB\n",
- direct_pages_count[PG_LEVEL_2M] << 11);
+ direct_pages_count[PGTABLE_LEVEL_PMD] << 11);
#else
seq_printf(m, "DirectMap4M: %8lu kB\n",
- direct_pages_count[PG_LEVEL_2M] << 12);
+ direct_pages_count[PGTABLE_LEVEL_PMD] << 12);
#endif
if (direct_gbpages)
seq_printf(m, "DirectMap1G: %8lu kB\n",
- direct_pages_count[PG_LEVEL_1G] << 20);
+ direct_pages_count[PGTABLE_LEVEL_PUD] << 20);
}
#else
static inline void split_page_count(int level) { }
@@ -164,7 +164,7 @@ static inline void cpa_inc_4k_install(void)
static inline void cpa_inc_lp_sameprot(int level)
{
- if (level == PG_LEVEL_1G)
+ if (level == PGTABLE_LEVEL_PUD)
cpa_1g_sameprot++;
else
cpa_2m_sameprot++;
@@ -172,7 +172,7 @@ static inline void cpa_inc_lp_sameprot(int level)
static inline void cpa_inc_lp_preserved(int level)
{
- if (level == PG_LEVEL_1G)
+ if (level == PGTABLE_LEVEL_PUD)
cpa_1g_preserved++;
else
cpa_2m_preserved++;
@@ -577,7 +577,7 @@ static pgprotval_t protect_kernel_text_ro(unsigned long start,
* so the protections for kernel text and identity mappings have to
* be the same.
*/
- if (lookup_address(start, &level) && (level != PG_LEVEL_4K))
+ if (lookup_address(start, &level) && (level != PGTABLE_LEVEL_PTE))
return _PAGE_RW;
return 0;
}
@@ -721,14 +721,14 @@ pte_t *lookup_address_in_pgd_attr(pgd_t *pgd, unsigned long address,
pud_t *pud;
pmd_t *pmd;
- *level = PG_LEVEL_256T;
+ *level = PGTABLE_LEVEL_PGD;
*nx = false;
*rw = true;
if (pgd_none(*pgd))
return NULL;
- *level = PG_LEVEL_512G;
+ *level = PGTABLE_LEVEL_P4D;
*nx |= pgd_flags(*pgd) & _PAGE_NX;
*rw &= !!(pgd_flags(*pgd) & _PAGE_RW);
@@ -739,7 +739,7 @@ pte_t *lookup_address_in_pgd_attr(pgd_t *pgd, unsigned long address,
if (p4d_leaf(*p4d) || !p4d_present(*p4d))
return (pte_t *)p4d;
- *level = PG_LEVEL_1G;
+ *level = PGTABLE_LEVEL_PUD;
*nx |= p4d_flags(*p4d) & _PAGE_NX;
*rw &= !!(p4d_flags(*p4d) & _PAGE_RW);
@@ -750,7 +750,7 @@ pte_t *lookup_address_in_pgd_attr(pgd_t *pgd, unsigned long address,
if (pud_leaf(*pud) || !pud_present(*pud))
return (pte_t *)pud;
- *level = PG_LEVEL_2M;
+ *level = PGTABLE_LEVEL_PMD;
*nx |= pud_flags(*pud) & _PAGE_NX;
*rw &= !!(pud_flags(*pud) & _PAGE_RW);
@@ -761,7 +761,7 @@ pte_t *lookup_address_in_pgd_attr(pgd_t *pgd, unsigned long address,
if (pmd_leaf(*pmd) || !pmd_present(*pmd))
return (pte_t *)pmd;
- *level = PG_LEVEL_4K;
+ *level = PGTABLE_LEVEL_PTE;
*nx |= pmd_flags(*pmd) & _PAGE_NX;
*rw &= !!(pmd_flags(*pmd) & _PAGE_RW);
@@ -849,9 +849,9 @@ pmd_t *lookup_pmd_address(unsigned long address)
phys_addr_t slow_virt_to_phys(void *__virt_addr)
{
unsigned long virt_addr = (unsigned long)__virt_addr;
+ enum pgtable_level level;
phys_addr_t phys_addr;
unsigned long offset;
- enum pg_level level;
pte_t *pte;
pte = lookup_address(virt_addr, &level);
@@ -863,11 +863,11 @@ phys_addr_t slow_virt_to_phys(void *__virt_addr)
* make 32-PAE kernel work correctly.
*/
switch (level) {
- case PG_LEVEL_1G:
+ case PGTABLE_LEVEL_PUD:
phys_addr = (phys_addr_t)pud_pfn(*(pud_t *)pte) << PAGE_SHIFT;
offset = virt_addr & ~PUD_MASK;
break;
- case PG_LEVEL_2M:
+ case PGTABLE_LEVEL_PMD:
phys_addr = (phys_addr_t)pmd_pfn(*(pmd_t *)pte) << PAGE_SHIFT;
offset = virt_addr & ~PMD_MASK;
break;
@@ -929,8 +929,8 @@ static int __should_split_large_page(pte_t *kpte, unsigned long address,
{
unsigned long numpages, pmask, psize, lpaddr, pfn, old_pfn;
pgprot_t old_prot, new_prot, req_prot, chk_prot;
+ enum pgtable_level level;
pte_t new_pte, *tmp;
- enum pg_level level;
bool nx, rw;
/*
@@ -942,12 +942,12 @@ static int __should_split_large_page(pte_t *kpte, unsigned long address,
return 1;
switch (level) {
- case PG_LEVEL_2M:
+ case PGTABLE_LEVEL_PMD:
old_prot = pmd_pgprot(*(pmd_t *)kpte);
old_pfn = pmd_pfn(*(pmd_t *)kpte);
cpa_inc_2m_checked();
break;
- case PG_LEVEL_1G:
+ case PGTABLE_LEVEL_PUD:
old_prot = pud_pgprot(*(pud_t *)kpte);
old_pfn = pud_pfn(*(pud_t *)kpte);
cpa_inc_1g_checked();
@@ -1148,7 +1148,7 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address,
paravirt_alloc_pte(&init_mm, page_to_pfn(base));
switch (level) {
- case PG_LEVEL_2M:
+ case PGTABLE_LEVEL_PMD:
ref_prot = pmd_pgprot(*(pmd_t *)kpte);
/*
* Clear PSE (aka _PAGE_PAT) and move
@@ -1160,7 +1160,7 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address,
lpinc = PAGE_SIZE;
break;
- case PG_LEVEL_1G:
+ case PGTABLE_LEVEL_PUD:
ref_prot = pud_pgprot(*(pud_t *)kpte);
ref_pfn = pud_pfn(*(pud_t *)kpte);
pfninc = PMD_SIZE >> PAGE_SHIFT;
@@ -1311,7 +1311,7 @@ static int collapse_pmd_page(pmd_t *pmd, unsigned long addr,
}
if (virt_addr_valid(addr) && pfn_range_is_mapped(pfn, pfn + 1))
- collapse_page_count(PG_LEVEL_2M);
+ collapse_page_count(PGTABLE_LEVEL_PMD);
return 1;
}
@@ -1358,7 +1358,7 @@ static int collapse_pud_page(pud_t *pud, unsigned long addr,
set_pud(pud, pfn_pud(pfn, pmd_pgprot(first)));
if (virt_addr_valid(addr) && pfn_range_is_mapped(pfn, pfn + 1))
- collapse_page_count(PG_LEVEL_1G);
+ collapse_page_count(PGTABLE_LEVEL_PUD);
return 1;
}
@@ -1860,7 +1860,7 @@ static int __change_page_attr(struct cpa_data *cpa, int primary)
if (pte_none(old_pte))
return __cpa_process_fault(cpa, address, primary);
- if (level == PG_LEVEL_4K) {
+ if (level == PGTABLE_LEVEL_PTE) {
pte_t new_pte;
pgprot_t old_prot = pte_pgprot(old_pte);
pgprot_t new_prot = pte_pgprot(old_pte);
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 2981e386da7b..3889bc2a1f76 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -2295,16 +2295,20 @@ static inline bool arch_has_pfn_modify_check(void)
typedef unsigned int pgtbl_mod_mask;
enum pgtable_level {
- PGTABLE_LEVEL_PTE = 0,
+ PGTABLE_LEVEL_NONE = 0,
+ PGTABLE_LEVEL_PTE,
PGTABLE_LEVEL_PMD,
PGTABLE_LEVEL_PUD,
PGTABLE_LEVEL_P4D,
PGTABLE_LEVEL_PGD,
+ PGTABLE_LEVEL_NUM,
};
static inline const char *pgtable_level_to_str(enum pgtable_level level)
{
switch (level) {
+ case PGTABLE_LEVEL_NONE:
+ return "none";
case PGTABLE_LEVEL_PTE:
return "pte";
case PGTABLE_LEVEL_PMD:
--
2.53.0